Manufacturing method of semiconductor and manufacturing method of semiconductor device

ABSTRACT

The nickel element is provided selectively, i.e., adjacent to part of the surface of an amorphous silicon film in a long and narrow opening. The amorphous silicon film is irradiated with linear infrared light beams emitted from respective linear infrared lamps while scanned with the linear beams perpendicularly to the longitudinal direction of the opening. The longitudinal direction of the linear beams are set coincident with that of the opening. The infrared light beams are absorbed by the silicon film mainly as thermal energy, whereby a negative temperature gradient is formed in the silicon film. The temperature gradient moves as the lamps are moved for the scanning. The direction of the negative temperature gradient is set coincident with the lamp movement direction and an intended crystal growth direction, which enables crystal growth to proceed parallel with a substrate uniformly over a long distance.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of forming a semiconductorfilm comprising silicon or silicon compound having crystallinity over aninsulating surface.

2. Description of the Related Art

A conventional technique is known in which a silicon film is formed overa glass or quartz substrate and a thin-film transistor (hereinafterreferred to as "TFT") is formed by using the thus-formed silicon film.

The TFT is mainly used in the active matrix liquid crystal displaydevice. The TFT is generally classified into the TFT using an amorphoussilicon film and the TFT using a crystalline silicon film.

At present, the TFT using an amorphous silicon film is the mainstream.However, the TFT using an amorphous silicon film is low in operationspeed and hence its applicability is limited for purposes of reducingthe size of a displayed image and displaying a high-speed movingpicture.

Further, it is also attempted to constitute, by using TFTs, variouscircuits that are conventionally implemented as ICs. In this case, theoperation speed of the TFT using an amorphous silicon film is much lowerthan a required value.

In view of the above, the TFT using a crystalline silicon film which isexpected to operate at higher speed is now being studied extensively.

Among well known methods for obtaining a crystalline silicon film are:

(1) forming a crystalline silicon film directly by CVD or the like;

(2) crystallizing an amorphous silicon film by a heat treatment;

(3) crystallizing an amorphous silicon film by irradiating it with laserlight; and

(4) crystallizing an amorphous silicon film by irradiating it withstrong light such as infrared light.

Among the above methods, methods (2)-(4) are mainly used.

Although method (2) is advantageous in that it can easily provide alarge-area film, the heat treatment temperature should be high and thequality of a resulting film is insufficient.

Although method (3) is advantageous in that thermal damage does notreach a glass substrate and a film having superior crystallinity can beobtained, it is difficult for method (3) to provide a large-area filmand the reproducibility of a process is low.

Although method (4) can easily provide a large-area film, the quality ofa resulting film is insufficient.

Studies of the present inventors revealed that the crystallization of anamorphous film can be accelerated by using a metal element typified bynickel (refer to Japanese Unexamined Patent Publication Nos. Hei.6-232059 and Hei. 7-321339).

By combining the crystallization technique using a metal element withmethods (2)-(4), a crystalline silicon film can be obtained that hassuch high film quality as could not be obtained so far.

However, the crystallinity thus obtained is still insufficient ascompared to that of a single crystal silicon wafer and thecharacteristics of a resulting TFT are far lower than those of acurrently available insulated-gate field-effect transistor thatconstitutes an IC. In particular, there is a serious problem thatvariations in device characteristics are large.

This is because grain boundaries exist in an uncontrollable state in acrystalline silicon film, i.e., in the channel of a TFT. In particular,since the grain boundaries extending direction cannot be controlled, thedevice characteristics vary to a large extent due to differences inextending directions of grain boundaries existing in the channels, whichnecessarily occur when a large number of devices are formed.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a technique forobtaining a crystalline silicon film that can provide superior TFTcharacteristics on a substrate having an insulating surface.

According to one aspect of the invention, there is provided a method forcrystallizing at least part of an amorphous film made of silicon or asilicon compound by using a metal element for acceleratingcrystallization, comprising the steps of introducing the metal elementinto part of the amorphous film; and forming a temperature gradient inthe amorphous film and causing crystal growth from a region where themetal element is introduced to another region by utilizing thetemperature gradient.

According to another aspect of the invention, there is provided a methodfor crystallizing at least part of an amorphous film made of silicon ora silicon compound by using a metal element for acceleratingcrystallization, comprising the steps of introducing the metal elementinto part of the amorphous film; and forming a temperature gradient inthe amorphous film in a direction extending from a region where themetal element is introduced to another region and causing crystal growthin the temperature gradient direction.

According to a further aspect of the invention, there is provided amethod for crystallizing at least part of an amorphous film made ofsilicon or a silicon compound by using a metal element for acceleratingcrystallization, comprising the steps of introducing the metal elementinto part of the amorphous film; and causing the metal element todiffuse in a predetermined direction by utilizing the temperaturegradient and causing crystal growth to proceed selectively in thepredetermined direction.

In each of the three aspects of the invention, it is preferable to movethe temperature gradient in the direction of the crystal growth, tothereby facilitate crystal growth in a direction parallel with theamorphous film.

Crystal growth in a direction parallel with the amorphous film can befacilitated by moving the temperature gradient in the direction of thecrystal growth at a speed corresponding to the rate of the crystalgrowth. This is particularly effective in obtaining a long crystalgrowth direction.

It is simple and convenient to form the temperature gradient byirradiation with linear infrared light. A means for instantaneouslymelting and solidifying a surface portion of a silicon film, such as ameans using ultraviolet pulse laser light, cannot be used becauseactually it does not form a temperature gradient.

From the viewpoint of reproducibility and effects, it is preferable touse nickel as the metal element for accelerating the crystallization.

The metal element may be one or a plurality of elements selected fromFe, Co, Ni, Cu, Ru, Rh, Pd, Os, Ir, Pt, and Au.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C show a step of obtaining a crystalline silicon filmaccording to a first embodiment of the present invention;

FIGS. 2A-2E shows a manufacturing process of a TFT (thin-filmtransistor) according to the first embodiment;

FIG. 3 is a perspective view corresponding to FIG. 1A;

FIG. 4 is a perspective view corresponding to FIG. 1B;

FIGS. 5A-5F schematically show various apparatuses according to a tenthembodiment of the invention; and

FIGS. 6A and 6B shows a step of obtaining a crystalline silicon filmaccording to a second embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

To practice the invention, it is important to form a negativetemperature gradient in the direction of crystal growth that isperformed by utilizing a metal element.

A specific example for realizing the above concept will be describedbelow with reference to FIGS. 1A-1B (sectional views) and FIG. 4(perspective view).

First, as shown in FIG. 1A, the nickel element is provided selectivelyadjacent to the surface of an amorphous silicon film 102, i.e., adjacentto a part of the surface of the amorphous silicon film (the region of anopening 104). The region where the nickel element is introduced has alinear shape that is long in the direction perpendicular to the papersurface.

Then, linear infrared light emitted from each of linear infrared lamps107 is reflected by each of reflecting plates 106, whereby the amorphoussilicon film 102 is irradiated with linear infrared light beams whilebeing scanned in a direction 100. The longitudinal direction of thelinear beams is set coincident with that of the opening 104 (i.e., theextending direction of the nickel introduction region).

The infrared light is absorbed by the silicon film 102 mainly as thermalenergy, whereby a temperature gradient shown in FIG. 1C is formed. Thetemperature gradient formed in the silicon film 102 moves as the lamp107 is moved in the direction 100.

The direction (indicated by numeral 10 in FIGS. 1B and 1C) of thenegative temperature gradient is set coincident with the lamp movementdirection 100 and the direction (indicated by numeral 108 in FIG. 1B) ofthe intended crystal growth.

In the above manner, the crystal growth can be performed in thedirection 108 parallel with a substrate 101 uniformly over a longdistance.

Crystal growth proceeds in the direction 108 parallel with the substrate101 by merely performing a heat treatment in a heating furnace withoutconducting lamp irradiation.

In the invention disclosed in the specification, it is important to setthe direction of the temperature gradient caused by the lamp irradiationand the lamp movement direction coincident with the direction of crystalgrowth that proceeds by the heat treatment.

This is meaningful in the following points.

In the crystallization technique utilizing a metal element,crystallization proceeds as the metal element diffuses from a particularregion (in the case of FIGS. 1A and 1B, the opening 104 is formed) toother regions in the silicon film.

As in the case of impurities diffusion in a semiconductor, the metalelement diffuses, with priority, from a region that is high in energystate to a region that is low in energy state.

Since the crystallization using the metal element proceeds inassociation with the diffusion of the metal element, forcing thediffusion of the metal element leads to control of the crystal growth.

That is, by forming a negative temperature gradient in a direction whichcoincides with the direction of intended crystal growth, the metalelement can be diffused intentionally in such a direction. Intentionallymaking the diffusion direction of the metal element coincide with acertain direction means intentional acceleration of crystal growth insuch a direction.

In this manner, crystal growth can be accelerated in a particulardirection.

It is also important to set the temperature gradient movement speed(specifically the lamp movement speed) in accordance with the crystalgrowth rate. This is to cause uniform crystal growth over a longdistance gradually (the movement is performed in a step-like mannerdepending on the crystal growth states) so as to keep the states of thecrystal growth (including the temperature gradient state in the siliconfilm).

Further, where crystal growth is performed by forming a temperaturegradient as shown in FIGS. 1B and 1C, a phenomenon can be restrainedthat the crystallization without utilizing the action of the metalelement obstructs the crystal growth that is caused by utilizing themetal element so as to proceed parallel with the substrate 101.

The crystal growth parallel with the substrate 101 that is caused byutilizing the action of the metal element is stopped in a region wherethe ordinary crystallization (in general, crystal growth proceeds in anamorphous silicon film by applying energy to it) proceeds that is notcaused by utilizing the action of the metal element. This is a factor ofreducing the crystal growth length in the direction 108.

According to the invention, by forming a negative temperature gradient,it is possible to reduce the energy to be applied to a region wherecrystal growth with a metal element is intended. Accordingly, it ispossible to avoid the above inconvenience.

In a region where crystal growth has been performed by the above method,crystal growth directions are well equalized and extending directions ofgrain boundaries well coincide with those crystal growth directions.Further, intervals between grain boundaries can be made approximatelyequal to each other.

When a number of TFTs are formed by utilizing the above crystalstructure, the form of existence of crystal boundaries in the channelregion can be made uniform among the TFTs. As a result, variations incharacteristics among the TFTs can be restrained.

Embodiment 1

FIGS. 1A-1C and 2A-2E show a manufacturing method according to thisembodiment. First, as shown in FIG. 1A, a 500-Å-thick amorphous siliconfilm 102 is formed on a quartz substrate 101 by low-pressure thermalCVD.

Then, a 700-Å-thick silicon oxide film (not shown) is formed by plasmaCVD and an opening 104 is formed therein to form a mask 103. The opening104 is formed so as to have a linear shape (slit shape) extendingperpendicularly to the paper surface of FIGS. 1A and 1B.

FIG. 3 is a perspective view corresponding to FIG. 1A. To describe thestructure in a simplified manner, FIG. 3 is drawn in such a manner thatthe opening 104 reaches two sidelines of the substrate. However, inpracticing the invention, the opening 104 need not always have such ashape.

Next, a nickel acetate salt solution containing the nickel element at 10ppm (in terms of weight) is applied and an excess of the solution isremoved with a spin coater. In this state, the nickel element is held incontact with the surface as indicated by numeral 105 in FIG. 1A.

The state of FIG. 1A is thus obtained.

Then, annealing is performed by using a linear lamp annealing apparatus.The lamp annealing apparatus is so configured as to enable irradiationwith linear beams by causing infrared light that is emitted from each oflong and narrow, rod-like lamps 107 to be reflected by each ofreflecting plates 106 (see FIGS. 1B and 4).

The positional relationship between the sample and the lamps 107 is suchas to be shown in FIG. 4. The crystallization is performed as follows:

(1) The longitudinal direction of the beams is set coincident with thatof the opening 104.

(2) The linear infrared light beams are moved in the direction(indicated by numeral 100 in FIG. 1B) perpendicular to the linear beamsat a given speed starting from the opening 104 or a position close toit.

As a result, a region irradiated with the linear infrared light beams isheated to about 800° C. in a short while. The nickel element is providedadjacent to (held in contact with) the surface of the amorphous siliconfilm 102 in the region of the opening 104, and it diffuses into theamorphous silicon film 102 as it is irradiated with the infrared lightbeams. Crystal growth proceeds in a direction 108 due to the action ofthe diffused nickel element and energy supplied by the infrared lightbeams.

It is preferred that the scanning speed of the infrared light beams beset equal to the crystal growth rate. The appropriate scanning speed ofthe infrared light beams needs to be determined by conducting apreliminary experiment because it depends on the thickness and the filmquality of the amorphous silicon film 102, the irradiation intensity andthe spectrum of the infrared light beams, the heat capacity of thesubstrate 101, and other factors.

It is also important that a temperature gradient be formed in thesilicon film so as to have a temperature profile as shown in FIGS. 1Band 1C. The temperature profile (temperature gradient state) is adjustedby changing the type and/of the positions of the reflecting plates 106and the positions of the lamps 107.

The crystal growth proceeds perpendicularly to the longitudinaldirection of the opening 104 in such a manner that growth directions aregenerally equal to each other.

FIG. 4 schematically shows a state that a region 400 has beencrystallized by the irradiation and the scanning with the linear lightbeams emitted from the lamps 107. Crystal growth directions areindicated by numeral 108.

In the above manner, a crystalline silicon film 109 is obtained in whichthe directions of the crystal growth that starts from the region of theopening 104 are well equalized with the direction indicated by numeral108 in FIG. 2A.

After the crystalline silicon film 109 is obtained, the silicon oxidefilm mask 103 is removed.

Then, the nickel element is removed from the film 109. Specifically, a300-Å-thick thermal oxidation film is formed by performing a heattreatment at 950° C. for 30 minutes in an oxygen atmosphere containingHCl at 3 volume percent. The nickel element is removed from the film 109during this course.

In this step, the nickel element evaporates as nickel chloride and isthereby eliminated outside.

The thickness of the crystalline silicon film 109 decreases to 350 Å asa result of the formation of the thermal oxidation film.

Next, the thus-formed thermal oxidation film is removed. The crystallinesilicon film 109 is patterned into a pattern of become the active layer(indicated by numeral 110 in FIG. 2B) of a TFT.

A gate insulating film 111 is then formed. Specifically, a 500-Å-thicksilicon oxide film is formed by plasma CVD and then a 200-Å-thickthermal oxidation film is formed. The thermal oxidation film is formedinside the silicon oxide film that has been formed by CVD, i.e., on thesurface of the active layer 110.

A 250-Å-thick active layer 110 and a 700-Å-thick gate insulating film111 covering the active layer 110 are thus formed.

Thereafter, an aluminum film containing scandium at 0.18 wt % is formedby sputtering and then patterned into a starting member of a gateelectrode.

The reason for having the aluminum film contain scandium is to preventformation of protrusions called hillocks and whiskers in later steps.

An anodic oxide layer 113 (it is not appropriate to call this layer afilm) and an anodic oxide film 114 are formed by performing anodizationin the following manner with the gate electrode starting member used asthe anode.

First, the porous anodic oxide layer 113 is formed by performinganodization in a state that a resist mask (not shown) that was used inpatterning the aluminum film is left.

The anodic oxide film 114 that is dense in film quality is then formedby again performing anodization after removing the resist mask.

The growth lengths of the porous anodic oxide layer 113 and the denseanodic oxide film 114 are set at 400 nm and 80 nm, respectively.

An anodic oxide film can selectively be made porous or dense dependingon the electrolyte used in the anodization.

The state of FIG. 2B is thus obtained. Subsequently, the exposed part ofthe silicon oxide film 111 is removed to leave a gate insulating film115 (see FIG. 2C).

Then, after the porous anodic oxide layer 113 is removed, the activelayer 110 is doped with P (phosphorus) by plasma doping. As a result, asource region 116, a drain region 120, low-concentration impurityregions (high-resistivity regions) 117 and 119, and a channel formingregion 118 are formed in a self-aligned manner (see FIG. 2D).

Subsequently, irradiation with laser light or infrared light isperformed to activate the dopant introduced in the above step and torepair damage of the doped regions through annealing.

Then, a silicon nitride film 121 and a polyimide resin film 122 areformed as an interlayer insulating film. After contact holes are formedthrough the films 121 and 122, a source electrode 123 and a drainelectrode 124 are formed. An n-channel thin-film transistor is thuscompleted (see FIG. 2E).

By employing the manufacturing process of this embodiment, a crystallinesilicon film having superior crystallinity can be formed over a largearea.

Embodiment 2

According to this embodiment, in the annealing step of the firstembodiment that uses linear infrared light beams, auxiliary lamps arearranged in addition to the main lamps 107. The preliminary heating isperformed on a region to be irradiated by the main lamps 107.

In this embodiment, auxiliary lamps 603 are disposed ahead of main lamps601 as shown in FIG. 6A. Reflecting plates 602 are provided only for themain lamps 601, whereby a temperature gradient as shown in FIG. 6B isformed.

The crystal growth states can be changed by altering the shape of thetemperature gradient.

Embodiment 3

According to this embodiment, in the constitution of the firstembodiment, a silicon film is scanned with linear infrared light beamsby moving the substrate rather than the lamp system.

The relative movement relationship between the substrate and the lampsystem in this embodiment is the same as in the first embodiment.

Embodiment 4

According to this embodiment, in the constitution of the firstembodiment, silicon or silicide is used to form the gate electrode of aTFT.

In this case, by virtue of high heat resistance of the gate electrode,the annealing to be performed after the impurity ion doping can beperformed by a heat treatment.

Embodiment 5

According to this embodiment, in the constitution of the firstembodiment, a TFT to be formed is of the bottom gate type structure. Abottom gate type TFT has been put into practical use in such a manner asto use an amorphous silicon film. Therefore, there is an advantage thata manufacturing process of this embodiment a manufacturing process of abottom gate type TFT using an amorphous silicon film can be partiallycommonized.

Embodiment 6

According to this embodiment, a p-channel TFT and an n-channel TFT areformed on the same substrate by using the crystallization technique ofthis invention and a complementary circuit of those TFTs is formed.

In this embodiment, both of doping for imparting p-type conductivity anddoping for imparting n-type conductivity need to be performed toseparately provide the two types of channels.

Embodiment 7

According to this embodiment, in the constitution of the firstembodiment, a semiconductor film of a silicon compound represented bySi_(x) Ge_(1-x) is used instead of a silicon film. The invention canalso be applied to a compound semiconductor containing silicon.

Embodiment 8

According to this embodiment, in the constitution of the firstembodiment, a polysilicon substrate is used as the substrate.

The polysilicon substrate that is used for the solar battery cannot beacquired at as low a price as the glass substrate.

In general, the polysilicon substrate is high in both impurityconcentration and defect density and hence cannot be used as an ICsubstrate.

However, where the polysilicon substrate is used for forming a TFT, itshigh impurity concentration and defect density are not serious problems.

In this embodiment, a silicon oxide film is formed on the surface of apolysilicon substrate by plasma CVD and a thermal oxidation film isformed thereon to provide an insulating surface. A TFT is formed on theinsulating surface by the method described in the first embodiment.

Embodiment 9

According to this embodiment, in the constitution of the firstembodiment, nickel is introduced by ion implantation. In this case, thenickel introduction amount can be controlled precisely. Further, aresist material can be used to form the mask.

Embodiment 10

This embodiment is directed to examples of electronic apparatuses thatuse an integrated circuit constituted of TFTs. The lo invention can beapplied to a circuit constituted of TFTs that are formed on a substratehaving a proper insulating surface. FIGS. 5A-5F outline the respectiveapparatuses.

FIG. 5A shows a portable information processing terminal having afunction of performing communication via telephone lines.

In this electronic apparatus, an integrated circuit 2006 that is acomposite circuit according to the invention is incorporated in a mainbody 2001. The electronic circuit further has an active matrix liquidcrystal display 2005, a camera section 2002 for capturing an image, anda manipulation switch 2004.

FIG. 5B shows an electronic apparatus called a head-mounted display,which has a function of virtually displaying, when mounted on a head, animage in front of the eyes. A main body 2101 is mounted on a head with aband 2103. An image is formed by liquid crystal display devices 2102corresponding to the respective eyes.

FIG. 5C shows a car navigation apparatus. This electronic apparatus hasa function of displaying map information and other various kinds ofinformation based on signals transmitted from an artificial satellite.Information transmitted from the satellite and received by an antenna2204 is processed by electronic circuits incorporated in a main body2201 and necessary information is displayed on a liquid crystal displaydevice 2202. The apparatus is manipulated through manipulation switches2203.

FIG. 5D shows a cellular telephone. In this electronic apparatus, a mainbody 2301 is provided with an antenna 2306, a voice output section 2302,a liquid crystal display device 2304, manipulation switches 2305, and avoice input section 2303.

An electronic apparatus shown in FIG. 5E is a portable imaging apparatuscalled a video camera. In this electronic apparatus, a main body 2401has, on an opening/closing member, a liquid crystal display 2402 andmanipulation switches 2404.

The main body 2401 is further provided with an image receiving section2406, integrated circuits 2407, a sound input section 2403, manipulationswitches 2404, and a battery 2405.

An electronic apparatus shown in FIG. 5F is a projection liquid crystaldisplay device. In this apparatus, a main body 2501 is provided with alight source 2502, a liquid crystal display device 2503, and an opticalsystem 2504. This apparatus has a function of projecting an image onto ascreen 2505.

The liquid crystal display device used in each of the above electronicapparatuses may be of either a transmission type or a reflection type.The transmission type is advantageous in terms of displaycharacteristics while the reflection type is advantageous for thepurpose of lowering the power consumption or reducing the size andweight.

Flat panel displays such as an active matrix EL display and a plasmadisplay can be used as the display device.

By utilizing the invention, a crystalline silicon film that can providesuperior TFT characteristics can be obtained on a substrate having aninsulating surface.

In particular, by equalizing crystal growth directions, grain boundariesextending directions can also be made coincident with those crystalgrowth directions. This is very effective in equalizing devicecharacteristics of a number of devices because the states of grainboundaries in the active layer of each device can be made uniform amongthose devices.

Such a crystalline silicon film can be used to form thin-filmsemiconductor devices such sensors and a diode in addition to a TFT.

What is claimed is:
 1. A method for manufacturing semiconductor materialcomprising the steps of:introducing a metal element into a region of anamorphous semiconductor material, the metal element acceleratingcrystallization of the semiconductor film; crystallizing at least partof the semiconductor material by scanning with at least one pair ofupper and lower linear infrared lights in a predetermined direction,wherein said upper linear infrared light is located over saidsemiconductor material and said lower linear infrared light is locatedat an underside of said semiconductor material.
 2. A method according toclaim 1, wherein a temperature gradient is formed in said semiconductormaterial and extends in a direction from the region where the metalelement is introduced to another region of the semiconductor materialand coincides with the crystal growth direction.
 3. A method accordingto claim 2, wherein the metal element diffuses in said predetermineddirection by utilizing the temperature gradient and the crystal growthproceeds selectively in the predetermined direction.
 4. The methodaccording to claim 2, wherein the crystallizing step comprises of movingthe temperature gradient in a direction of the crystal growth to beproceeded, in order to make the direction of the crystal growth inparallel with the semiconductor material.
 5. The method according toclaim 2, wherein the crystallizing step comprises moving the temperaturegradient in a direction of the crystal growth at a speed correspondingto a rate of the crystal growth, to thereby make the direction of thecrystal growth parallel with the semiconductor material.
 6. The methodaccording to claim 1, wherein said semiconductor material comprisessilicon or silicon compound.
 7. The method according to claim 1, whereinthe metal element is nickel.
 8. The method according to claim 1, whereinthe metal element is one or a plurality of elements selected from thegroup consisting of Fe, Co, Ni, Cu, Ru, Rh, Pd, Os, Ir, Pt, and Au.
 9. Amethod for manufacturing semiconductor device comprising the stepsof:forming an amorphous semiconductor film over a substrate; introducinga metal element into a region of said amorphous semiconductor film, themetal element accelerating crystallization of the semiconductor film;crystallizing at least part of the semiconductor film by scanning withat least one pair of upper and lower linear infrared lights in apredetermined direction, wherein said upper linear infrared light islocated over said substrate and said lower linear infrared light islocated at a backside of said substrate.
 10. A method according to claim9, wherein a temperature gradient are formed in said semiconductor filmand extends in a direction from the region where the metal element isintroduced to another region of the semiconductor film and coincideswith the crystal growth direction.
 11. A method according to claim 10,wherein the metal element diffuses in a predetermined direction byutilizing the temperature gradient and the crystal growth proceedsselectively in the predetermined direction.
 12. The method according toclaim 10, wherein the crystallizing step comprises of moving thetemperature gradient in a direction of the crystal growth to beproceeded, in order to make the direction of the crystal growth inparallel with the semiconductor film.
 13. The method according to claim10, wherein the crystallizing step comprises moving the temperaturegradient in a direction of the crystal growth at a speed correspondingto a rate of the crystal growth, to thereby make the direction of thecrystal growth parallel with the amorphous film.
 14. The methodaccording to claim 9, wherein semiconductor film comprises silicon orsilicon compound.
 15. The method according to claim 9, wherein the metalelement is nickel.
 16. The method according to claim 9, wherein themetal element is one or a plurality of elements selected from the groupconsisting of Fe, Co, Ni, Cu, Ru, Rh, Pd, Os, Ir, Pt, and Au.
 17. Amethod for manufacturing semiconductor material comprising a stepof:crystallizing at least one portion of an amorphous semiconductormaterial by scanning the semiconductor material with at least one pairof linear infrared lights in a predetermined direction at a speedcorresponding to a rate of crystal growth, wherein one of said linearinfrared lights is located over said semiconductor material and theother one of said linear infrared lights is located at an underside ofsaid semiconductor material.
 18. The method according to claim 17,wherein the predetermined direction coincide with the direction of thecrystal growth.
 19. The method according to claim 17, wherein thecrystal growth expends in the direction parallel with the semiconductormaterial.
 20. The method according to claim 17, wherein thesemiconductor material comprises silicon or silicon compound.
 21. Themethod according to claim 17, wherein said semiconductor materialincludes at least one metal element selected from the group consistingof Fe, Co, Ni, Cu, Ru, Rh, Pd, Os, Ir, Pt, and Au.
 22. A method formanufacturing semiconductor device comprising the steps of:forming anamorphous semiconductor film over a substrate; and crystallizing atleast one portion of the semiconductor film by scanning thesemiconductor film with at least one pair of linear infrared lights in apredetermined direction at a speed corresponding to a rate of crystalgrowth, wherein one of said linear infrared lights is located over saidsubstrate and the other one of said linear infrared lights is located ata backside of said substrate.
 23. The method according to claim 22,wherein said semiconductor film includes at least one +metal elementselected from the group consisting of Fe, Co, Ni, Cu, Ru, Rh, Pd, Os,Ir, Pt, and Au.
 24. The method according to claim 22, wherein thesemiconductor film comprises silicon or silicon compound.
 25. A methodfor manufacturing semiconductor material comprising the stepsof:introducing a metal element into at least one region of an amorphoussemiconductor material, the metal element accelerating crystallizationof the semiconductor material; and crystallizing at least one portion ofthe semiconductor material by scanning the semiconductor material withat least one pair of upper and lower linear infrared lights in adirection from the region introduced the metal element to another partof the semiconductor material in order to form and move a temperaturegradient in the semiconductor material, wherein said upper linearinfrared light is located over said semiconductor material and saidlower linear infrared light is located at an underside of saidsemiconductor material.
 26. The method according to claim 25, whereinthe scanning direction coincide with the direction of crystal growth inthe semiconductor material.
 27. The method according to claim 25,wherein crystal growth in the semiconductor material expends in thedirection parallel with the semiconductor material.
 28. The methodaccording to claim 25, wherein the semiconductor material comprisessilicon or silicon compound.
 29. The method according to claim 25,wherein the metal element is one or a plurality of elements selectedfrom the group consisting of Fe, Co, Ni, Cu, Ru, Rh, Pd, Os, Ir, Pt, andAu.
 30. A method for manufacturing semiconductor device comprising thesteps of:introducing a metal element into at least one region of anamorphous semiconductor film, the metal element acceleratingcrystallization of the semiconductor film; and crystallizing at leastone portion of the semiconductor film by scanning the semiconductor filmwith at least one pair of upper and lower linear infrared lights in adirection from the region introduced the metal element to another partof the semiconductor film in order to form and move a temperaturegradient in the semiconductor film, wherein said upper linear infraredlight is located over said semiconductor film and said lower linearinfrared light is located at an underside of said semiconductor film.31. The method according to claim 30, wherein the scanning directioncoincide with the direction of crystal growth in the semiconductor film.32. The method according to claim 30, wherein crystal growth in thesemiconductor film expends in the direction parallel with thesemiconductor film.
 33. The method according to claim 30, wherein thesemiconductor film comprises silicon or silicon compound.
 34. The methodaccording to claim 30, wherein the metal element is one or a pluralityof elements selected from the group consisting of Fe, Co, Ni, Cu, Ru,Rh, Pd, Os, Ir, Pt, and Au.
 35. The method according to claim 9, whereinsaid device is an EL display device.
 36. The method according to claim22, wherein said device is an EL display device.
 37. The methodaccording to claim 30, wherein said device is an EL display device. 38.A method for manufacturing a semiconductor device comprising the stepsof:forming a semiconductor film over a substrate; introducing at leastone impurity element into said semiconductor film; and irradiating saidsemiconductor film by scanning with at least one pair of linear infraredlights in a predetermined direction, wherein one of said linear infraredlights is located over said substrate and the other one of said linearinfrared lights is located at a backside of said substrate.
 39. A methodaccording to claim 38 wherein said semiconductor film comprises siliconor silicon compound represented by Si_(x) Ge_(1-x).
 40. A methodaccording to claim 38 further comprising a step of forming gateelectrode over said semiconductor film with a gate insulating filminterposed therebetween.
 41. A method according to claim 38 furthercomprising a step of forming gate electrode over said substrate beforeforming said semiconductor film.
 42. A method according to claim 38wherein said semiconductor device having an EL display device.
 43. Amethod for manufacturing a semiconductor device comprising the stepsof:forming a semiconductor film over a substrate; introducing at leastone impurity element into selected portions of said semiconductor film;and activating said impunity element introduced in said portion byscanning said semiconductor film with at least one pair of linearinfrared lights in a predetermined direction, wherein one of said linearinfrared lights is located over said substrate and the other one of saidlinear infrared lights is located at a backside of said substrate.
 44. Amethod according to claim 43 wherein said semiconductor film comprisessilicon or silicon compound represented by Si_(x) Ge_(1-x).
 45. A methodaccording to claim 43 further comprising a step of forming gateelectrode over said semiconductor film with a gate insulating filminterposed therebetween.
 46. A method according to claim 43 furthercomprising a step of forming gate electrode over said substrate beforeforming said semiconductor film.
 47. A method according to claim 43wherein said semiconductor device having an EL display device.
 48. Amethod for manufacturing a semiconductor device comprising the stepsof:forming a semiconductor film over a substrate, said semiconductorfilm having at least a channel forming region and source and drainregions; irradiating said semiconductor film by scanning with at leastone pair of linear infrared lights in a predetermined direction in orderto activate said source and drain regions, wherein one of said linearinfrared lights is located over said substrate and the other one of saidlinear infrared lights is located at a backside of said substrate.
 49. Amethod according to claim 48 wherein said semiconductor film comprisessilicon or silicon compound represented by Si_(x) Ge_(1-x).
 50. A methodaccording to claim 48 further comprising a step of forming gateelectrode over said semiconductor film with a gate insulating filminterposed therebetween.
 51. A method according to claim 48 furthercomprising a step of forming gate electrode over said substrate beforeforming said semiconductor film.
 52. A method according to claim 48wherein said semiconductor device having an EL display device.
 53. Amethod for manufacturing a semiconductor device comprising the stepsof:forming a semiconductor film over a substrate; and irradiating saidsemiconductor film with at least one pair of linear infrared lightswhile moving said substrate in a direction perpendicular to the linearinfrared lights, wherein one of said linear infrared lights is locatedover said substrate and the other one of said linear infrared lights islocated at a backside of said substrate.
 54. A method according to claim53 wherein said semiconductor film comprises silicon or silicon compoundrepresented by Si_(x) Ge_(1-x).
 55. A method according to claim 53further comprising a step of forming gate electrode over saidsemiconductor film with a gate insulating film interposed therebetween.56. A method according to claim 53 further comprising a step of forminggate electrode over said substrate before forming said semiconductorfilm.
 57. A method according to claim 53 wherein said semiconductordevice having an EL display device.
 58. A method for manufacturing asemiconductor device comprising the steps of:forming a semiconductorfilm over a substrate; and crystallizing said semiconductor film byirradiating said semiconductor film with at least one pair of linearinfrared lights while moving said substrate in a perpendicular to thelinear infrared lights, wherein one of said linear infrared lights islocated over said substrate and the other one of said linear infraredlights is located at a backside of said substrate.
 59. A methodaccording to claim 58 wherein said semiconductor film comprises siliconor silicon compound represented by Si_(x) Ge_(1-x).
 60. A methodaccording to claim 58 further comprising a step of forming gateelectrode over said semiconductor film with a gate insulating filminterposed therebetween.
 61. A method according to claim 58 furthercomprising a step of forming gate electrode over said substrate beforeforming said semiconductor film.
 62. A method according to claim 58wherein said semiconductor device having an EL display device.
 63. Amethod for manufacturing a semiconductor device comprising the stepsof:forming a semiconductor film over a substrate, said semiconductorfilm having at least a channel forming region and source and drainregions; and irradiating said semiconductor film with at least one pairof linear infrared lights while moving said substrate in a directionperpendicular to the linear infrared lights in order to activate saidsource and drain regions, wherein one of said linear infrared lights islocated over said substrate and the other one of said linear infraredlights is located at a backside of said substrate.
 64. A methodaccording to claim 63 wherein said semiconductor film comprises siliconor silicon compound represented by Si_(x) Ge_(1-x).
 65. A methodaccording to claim 63 further comprising a step of forming gateelectrode over said semiconductor film with a gate insulating filminterposed therebetween.
 66. A method according to claim 63 furthercomprising a step of forming gate electrode over said substrate beforeforming said semiconductor film.
 67. A method according to claim 63wherein said semiconductor device having an EL display device.
 68. Amethod for manufacturing a semiconductor device comprising the stepsof:forming a semiconductor film over a substrate; and irradiating saidsemiconductor film with a plurality pairs of linear infrared lights byscanning said light in a direction perpendicular to a longitudinaldirection of the linear infrared lights, each of said pairs of pairs oflinear infrared lights consisting of an upper linear infrared light anda lower linear infrared light, wherein each upper linear infrared lightis located over said substrate and each lower linear infrared light islocated at a backside of said substrate.
 69. A method according to claim68 wherein said semiconductor film comprises silicon or silicon compoundrepresented by Si_(x) Ge_(1-x).
 70. A method according to claim 68further comprising a step of forming gate electrode over saidsemiconductor film with a gate insulating film interposed therebetween.71. A method according to claim 68 further comprising a step of forminggate electrode over said substrate before forming said semiconductorfilm.
 72. A method according to claim 68 wherein said semiconductordevice having an EL display device.
 73. A method for manufacturing asemiconductor device comprising the steps of:forming a semiconductorfilm over a substrate; and crystallizing said semiconductor film byscanning with a plurality of pairs of linear infrared lights in adirection perpendicular to a longitudinal direction of the linearinfrared lights, each of said pairs of pairs of linear infrared lightsconsisting of an upper linear infrared light and a lower linear infraredlight, wherein each upper linear infrared light is located over saidsubstrate and each lower linear infrared light is located at a backsideof said substrate.
 74. A method according to claim 73 wherein saidsemiconductor film comprises silicon or silicon compound represented bySi_(x) Ge_(1-x).
 75. A method according to claim 73 further comprising astep of forming gate electrode over said semiconductor film with a gateinsulating film interposed therebetween.
 76. A method according to claim73 further comprising a step of forming gate electrode over saidsubstrate before forming said semiconductor film.
 77. A method accordingto claim 73 wherein said semiconductor device having an EL displaydevice.
 78. A method for manufacturing a semiconductor device comprisingthe steps of:forming a semiconductor film over a substrate; introducingat least one impurity element into said semiconductor film; and thenirradiating said semiconductor film with a plurality pairs of linearinfrared lights by scanning said light in a direction perpendicular to alongitudinal direction of the linear infrared lights, each of said pairsof pairs of linear infrared lights consisting of an upper linearinfrared light and a lower linear infrared light, wherein each upperlinear infrared light is located over said substrate and each lowerlinear infrared light is located at a backside of said substrate.
 79. Amethod according to claim 78 wherein said semiconductor film comprisessilicon or silicon compound represented by Si_(x) Ge_(1-x).
 80. A methodaccording to claim 78 further comprising a step of forming gateelectrode over said semiconductor film with a gate insulating filminterposed therebetween.
 81. A method according to claim 78 furthercomprising a step of forming gate electrode over said substrate beforeforming said semiconductor film.
 82. A method according to claim 78wherein said semiconductor device having an EL display device.